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3.5.6
Port 8 (P80 to P83)
Port 8 is 4-bit output port. Resetting sets output latch of P82 to "0" and set output
latches of P80, P81, and P83 to "1".
In addition to functioning as a output port, port 8 can also function as a output chip select
signal (
CS0
These settings operate by programming "1" to the corresponding bit of P8FC.
Resetting set all bits of P8FC to "0", these pits set output mode.
Reset
P8
Bit symbol
(0020H)
Read/Write
After reset
Bit symbol
P8FC
Read/Write
(0023H)
After reset
Function
Note 1: Read-modify-write instruction is prohibited for the registers P8FC.
Note 2: When set P82 pin as
P82 to "0" (P8<P82> = 0).
If set function register (P8FC<P82F> = 1) after set output latch to "1" (P8<P82> = 1), maybe operation become
to error because
to
).
CS3
Function control
(on bit basis)
P8FC write
Output latch
P8 write
P8 read
,
CS0
CS1
Figure 3.5.12 Port 8
Port 8 Register
7
6
5
Port 8 Function Register
7
6
5
after release reset, set function register (P8FC<P82F> = 1) in keep output latch of
CS
2
output don't output correctly.
CS
2
Figure 3.5.13 Register for Port 8
92CM22-62
S
A
Selector
B
,
,
CS2
CS3
4
3
P83
1
4
3
P83F
0
0: Port
0: Port
1:
1:
CS
3
TMP92CM22
P80 (
)
CS0
P81 (
)
CS1
P82 (
)
CS2
P83 (
)
CS3
2
1
0
P82
P81
P80
R/W
0
1
1
2
1
0
P82F
P81F
P80F
W
0
0
0
0: Port
0: Port
1:
1:
CS
2
CS
1
CS
0
2007-02-16
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